Factor and check x^2 + 0x - 16 = 0

x^2 + 0x - 16 = 0

(x )(x ) ( -4)( +4)=0

(x-4) (x+4) = 0

Check:

(x-4) (x+4) = 0

(x)(x) (x)(+4) (-4)(x) (-4)(+4)=0

x^2 +4x -4x -16=0

x^2 + 0x - 16 = 0